This grant proposal is a continuation of the program for the systematic study of psychotropic drugs on the Children's Service of Bellevue Psychiatric Hospital, New York. We plan to concentrate our efforts on preschool-age retarded schizophrenic and autistic children. We wish to evaluate new drugs that may be potentially useful for these severely-disturbed children, to carry out controlled studies of drugs that appear therapeutically promising, and to coordinate behavioral and biological changes on and off drugs. Individual patients will be followed longitudinally to evaluate long-term outcome of drug treatment and somatosexual maturation. The studies will be carried out in order to develop a more rational approach in pharmacotherapy for this population of children, to delineate biologically more meaningful diagnostic categories of subgroups, and to define "drug responders". This should lead to the use of more effective psychoactive agents in the treatment of children with severe behavioral disorders. BIBLIOGRAPHIC REFERENCES: Campbell, M. Clinical Trials of TRH (Thyrotropic Releasing Hormone). Introduction. Psychopharmacology Bulletin, 11:19-20, 1975. Petti, T.A., and Campbell, M. Imipramine and Seizures. American Journal of Psychiatry, 132:538-540, 1975.